Cable trays (sometimes called cable races) are found in commercial and industrial facilities, power generation facilities, manufacturing plants, and the like. These trays and their related hardware are used to support, guide, contain, and help manage cables, tubes, pipes, conduits, and wires that must be run from one part of the facility or plant to another. Examples of cable trays may be found in U.S. Pat. No. 4,232,845, U.S. Pat. No. 3,137,468, U.S. Pat. No. 4,432,519 and U.S. Pat. No. 6,498,296, which are incorporated herein by reference.
The primary requirement for a completed cable tray system is structural rigidity. In many applications, the cable tray system is also designed to minimize or eliminate electrical arcing between connected parts of the system by maintaining electrically conductive continuity in the event that the system becomes electrically energized.
Cable trays typically are formed from linear runs of trays connected together to span the length of a facility. Sections of trays are fastened together to achieve the requisite length and shape. Occasionally, an entire cable tray may be installed in a straight line without interruption. More often than not, however, previously installed or permanent structures, such as support columns, walls, and other cable trays, are obstacles to the installation of a linear cable tray and therefore require a cable tray to negotiate its path around these other structures and depart from its otherwise straight-line trajectory. In some circumstances, a cable tray running from one location to another within a single facility may need to change direction and elevation perhaps more than once along its path.
Ladder-type cable trays are known. These are constructed from spaced-apart rails to which rungs are welded to form a “ladder-like” framework or section that will support cables with less material. The latter tray sections are shipped to the jobsite where they are connected together, section by section.
Designs may need to be carefully and accurately drawn out in advance to be sure that the cable tray layout for a facility will be installed efficiently and accurately.
Even when the cable tray design is complete, flexibility may still be needed during the installation process in the field to achieve a satisfactory outcome. Accordingly, it would be advantageous to have flexibility in cable tray design to accommodate real world applications.